Sorry to bring up this older thread. But my problem exactly belongs to here but with a new error message.
The lauchner stuck also at 0% while patching gl_v2_0to5.zip with the following error (i started with TERA-Launcher.exe /window):

I downloaded the Install fix, deleted BOTH, the gl.version and gl_v2.version file, started the install fix and started the launcher again. Then it patches from gl_v2_-1to5 instead of gl_v2_0to5. the d3dcompiler_43.dll file got now a newer version and the patching process continues. (hopefully until the end ;-))

I am admin of the computer and I start the luncher as admin.
I made the download but it just keep freezing at 100% of ''applying patch''
I saw it this morning and I went do something else....
Even after 8 HOURS.It still on 100% and nothing hapend!
And yes I tried things that are writen in this forum and none of them worked.
I already downloaded the game like 1 year ago and I did not had one single problem
Now the luncher is buggy as hell and cant apply the patch.
So I simply cant play the game.

Downloaded the game for the first time and got stuck at "Applying Patch" too, tried the fix suggested by the op but didn't solved the issue.

Im just trying to try the game but can't even get it to start, plus, seems there's no "Happy Cloud" anymore so i had to download the whole 26gb of files, just to get stuck at patching the game for more than 12 hours now.

How would this encourage me to purchase the game or even think about going Elite after Tera's free release?

Hi, I've been stuck at Applying Patch part for hours now :/
first time i was stuck at 44% and now i'm stuck at 6% all the time

It was a clean download, had never modified any part of it so I don't understand why I'm getting this error... the fix on TeraEurope doesn't work for me either, I download and run and says its installed but tats it? is this how it's suppose to be? :/

I also used cmd to open the launcher and I was stuck at one of the maps "ASE_B_PoraElinu.gmp" and it also told me the "Game_-1to28.zip" cannot be extracted :/ it then went into qued mode, idle mode ...which I don't quite understand :/ the files are all there and the read only mode was unchecked...
I also checked to see if I have the game.version or gl.version, I have neither of those :/

Also after I unchecked the "Read-only mode" as an Admin for the folder the game is in, it keeps reverting back to Read only mode as well.....
On the launcher, the status says I am downloading at 11.3mB/s but all the status numbers are frozen and does not change even when I leave it on for 30 min....

Sorry for the really long post but I really wish someone could help me out, I've been at this for 2 whole days and it's driving me nuts....